Achilles Tendinopathy

Achilles tendinopathy represents a failed healing response in the tendon rather than true inflammation. Histologically, the tissue shows disorganized collagen fibers, increased ground substance, and neovascularization (new blood vessel ingrowth) — a pattern termed tendinosis. The two subtypes differ significantly:

Midportion Tendinopathy

• Located 2–6 cm proximal to the calcaneal insertion, in the relatively avascular "watershed zone"
• Most common in runners and jumping athletes aged 35–55
• Associated with training load spikes, hard surfaces, and calf inflexibility/weakness
• Tendon is visibly and palpably thickened; the "painful arc sign" (tenderness that moves with the tendon on dorsiflexion) helps distinguish intratendinous from paratendinous pathology
• Royal London Hospital test: dorsiflexing the ankle reduces pain when the tendon is squeezed, indicating intratendinous pathology (positive in true tendinopathy); if pain does not change, paratendinopathy is more likely

Insertional Tendinopathy

• Located at the posterior calcaneal attachment, often with a Haglund deformity (prominent posterosuperior calcaneal bony prominence) and retrocalcaneal bursitis
• Pain with direct shoe counter pressure; worse at the start of activity ("warm-up pain")
• Eccentric exercises that load the tendon in plantarflexion below neutral (heel drops off a step) are contraindicated here, as they compress the already-irritated insertion
• Posterior heel calcification and enthesophyte formation are common on X-ray

Why the Distinction Matters

Midportion and insertional tendinopathy look superficially similar but respond to fundamentally different rehabilitation programs. Applying the wrong protocol — particularly aggressive eccentric heel drops in insertional disease — can worsen symptoms significantly.

Treatment options

Achilles tendinopathy responds well to a structured loading program — most patients improve significantly within 3 months.

Frequently Asked Questions